I have both a 6000L and C1000 Zaurus, and was checking the battery output with a multimeter. Both batteries seem to have the same 3.7 volt output. Both batteries have 3 contacts, and voltage between the outside contacts are the same. And there is no voltage between the middle contact and either side (probably the middle contact is for charging [?] the battery). So I was thinking about fabricating a battery case that fits the 6000's battery compartment (except it will stick out about a 1/4" from the back to accomodate the thicker battery in the C1000). Then I propose to make some copper or brass contacts that are soldered to wires and to contacts on the other end. Then put the EA-BL08 battery in this box, with the contacts polarity matched up properly, and see if the 6000 can use the C1000's battery.

If it can, then I will have a 2000 mAh battery in the 6000 instead of a 1500 mAh battery. Also EA-BL08 batteries can be purchased much more cheaply than EA-BL09s.

The only thing I am not sure about is that the EA-BL09 says it is lithium polymer at the top, and lithium ion at the bottom of the same battery. (Not sure how it can be both?) The EA-BL08 is just labeled lithium ion.

Those of you who know about electronics see any obvious flaws with this plan? This shouldn't blow up my Zaurus should it?

I don't see any issues with it, unless you make some mistake like switching the contacts around, which may cause issues..

Another thing you may want to look at is fabricating your own battery (as long as you're making a new compartment anyway). I saw some at SparkFun that were 3.7v, 6000mAh and looked relatively small. Something like that may be fun (they were cheap, too, at 10 USD).

You may want to wait for a response from somebody who has a little better handle on things, though.

The middle contact is the termistor sensor. If you don't care about temperature of your battery (you should care to prevent explosion in fire), you can replace it by resistor of a decent value. If you will ignore this pin, Zaurus will reject your battery.

Unless you plan case hacking as well, simpler solution would be improving kernel charging code (to allow charging force off: If running from external battery, there is low benefit to charge internal battery from) and then use external charger connector. You wil lose few % of energy and you should provide 5V.

I don't see any issues with it, unless you make some mistake like switching the contacts around, which may cause issues..

Another thing you may want to look at is fabricating your own battery (as long as you're making a new compartment anyway). I saw some at SparkFun that were 3.7v, 6000mAh and looked relatively small. Something like that may be fun (they were cheap, too, at 10 USD).

You may want to wait for a response from somebody who has a little better handle on things, though.

HTH

Do these batteries have the center contact?

QUOTE(utx @ Jul 17 2008, 03:12 AM)

The middle contact is the termistor sensor. If you don't care about temperature of your battery (you should care to prevent explosion in fire), you can replace it by resistor of a decent value. If you will ignore this pin, Zaurus will reject your battery.

Unless you plan case hacking as well, simpler solution would be improving kernel charging code (to allow charging force off: If running from external battery, there is low benefit to charge internal battery from) and then use external charger connector. You wil lose few % of energy and you should provide 5V.

Are you talking about the C1000 battery, or the one Capn_Fish mentions? I was hoping that the center contact in the C1000 battery has the same circuitry. Meaning no need for the resister. Just plug-n-play.

No, I don't think so...I was more thinking of using that as a semi-external battery (keep the internal one, have this one attached with a switch to activate it acting as a charger. You probably need 5v for that, though...).

The middle contact is the termistor sensor. If you don't care about temperature of your battery (you should care to prevent explosion in fire), you can replace it by resistor of a decent value. If you will ignore this pin, Zaurus will reject your battery.

Are you talking about the C1000 battery, or the one Capn_Fish mentions? I was hoping that the center contact in the C1000 battery has the same circuitry. Meaning no need for the resister. Just plug-n-play.

Both batteries have temperature sensor contact and both SL-Cxxx and SL-6000 have batter temperature check circuit (well, it is half software thing, so you can hack it a bit). Actually, temperature sensor is mandatory for all Li-Ion/Li-Pol batteries, otherwise charging is slow or risky.

If you will provide an external power via the internal battery contacts, you have to provide correct value to the center contact, otherwise zaurus rejects to boot and LED will blink (people who purchased cheap third party batteries can tell you about it). I can ask my colleague for the value, as he built a fake battery.

If you will provide an external power via the AC plug, there is no need for any resistor, but as Capn_Fish wrote, you need 5V.

Then do you think if I use a thermal conductor (don't know if there is such a thing) to the middle contact, this would be safe to try? If so, can you suggest the part that would carry the temperatures from one contact to another?

No, I don't think so...I was more thinking of using that as a semi-external battery (keep the internal one, have this one attached with a switch to activate it acting as a charger. You probably need 5v for that, though...).

My idea was muddled/flawed (it was late last night), I guess.

I have a switchable voltage power supply from Radio Shack. My sl-c1000 will charge fine when it's switched as low as 4.5 volts (and I have checked the output with a multi-meter to ensure the 4.5 volt figure is accurate).

[attachment=5496:C1000_ba...y_in_box.jpg] I already have an external battery extender. It is my hope to make an internal battery. So my question is whether or not the C1000 battery is enough like the 6000's battery to be used with a home-made adapter. I'm hoping that since they are the same voltage, and same number of contacts, that they are compatible (other than being shaped different).

I started this about 2 years ago, originally thinking to put a battery holder with 3 NiMH 1.2 volt AA batteries in the battery holder and putting the make-shift battery adapter in the back of the Z instead of the battery that came with it. The problem with this was that I would have to remove the batteries to recharge them.

So my latest brilliant idea (?) was to use the C1000 battery in my battery box. Maybe it is easier to see what I intend with pictures:

EDIT: I intend to paint it flat black, and probably make a case to use with it. I have also thought about cutting open an iRiver USB adapter, and seeing if I can make it flat on the end that plugs into the Z, and fastening the other end into either the battery box or the case (so that I will have a typical USB host port, not needing to carry around an adapter).

To give an idea of the caae, here is one I already made. It allows me to use it in landscape mode with an IR keyboard. It is simply leather glued to a holder made out of HVAC galvanized sheet metal. As you can see from the comparison shot, it is about 5/8 inch less thick than the C1000 in it's PDair case. If I remade it 1/4 inch thicker to accommodate my battery hack, it would still be 3/8 inch less thick than PDair case.

I think (i. e. with no guarantee), that you can use NiMh batteries with say 2.7-3.6V using internal contacts and smart wiring of the middle contact.

But you cannot charge them. Charging technology and response of Ni-Mh and Li-Ion differ.

While for charging Li-Ion you need a constant voltage keeping the maximal current and temperature at defined value (if any of them exceeds, limit the current), for NiMh you need constant current keeping temperature (and internal resistence) in limit (checking for over-charging, better chargers could use pulses and response measure).

However the charging control chip inside Zaurus (Semtech SC801) is Ni-Mh capable (see the datasheet on my pages). In theory, the circuitry can be modified to charge Ni-Mh, but it would need a lot of hardware skills and circuitry study.

The holder on the photo has 4 battery slots, sou you can get 4.8-5V. It is sufficient for the AC jack, and you will not have to shutdown, reboot, set the clock to recharge them (if you keep internal battery as a backup source).

I gave up on my original idea (the AA battery holder with only 3 of the battery slots used), in favor of using the C1000 battery in my battery box. Do you think the built-in charging circuit can handle that?

I gave up on my original idea (the AA battery holder with only 3 of the battery slots used), in favor of using the C1000 battery in my battery box. Do you think the built-in charging circuit can handle that?

I think that yes. Trisoft sells battery chargers for older models and say, that they are compatible with new batteries after small mechanical modification. Maybe other Li-Ion/Li-Pol batteries may work as well.